1. Faculty of Electrical Engineering and Information Technology, Slovak University of Technology in Bratislava, Ilkovièova 3, Bratislava, SK-81219, Slovak Republic
2. University Centre of Electron Accelerators, Slovak Medical University, Ku kyselke 497, Trenèín, SK-91106, Slovak Republic
3. GSI Helmholzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, Darmstadt, D-64291, Germany